How much lye is too much lye...

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HLN80

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when I made my very first batch, the recipe was wrong, it called for 9oz of lye but after getting help from a sweet lady on here, she told me it should be 7.6oz. Total oils were 54oz. Anyway, that particular soap is still sitting on a shelf and I’m wondering if it might still be usable, how do I tell? it looks like all my other soaps.
 

shunt2011

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You can do 1 of two things. You can put it away and see if it becomes usable. Generally lye heavy soap will be okay after some time. Or you could re-batch it with the appropriate oils but adjusting the recipe until the lye equals what you used.

One other suggestion would be to make smaller batches. As a beginner when something goes wrong it can be an expensive mistake.
 

HLN80

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You can do 1 of two things. You can put it away and see if it becomes usable. Generally lye heavy soap will be okay after some time. Or you could re-batch it with the appropriate oils but adjusting the recipe until the lye equals what you used.

One other suggestion would be to make smaller batches. As a beginner when something goes wrong it can be an expensive mistake.
Thank you so much! And you are right, I should have made a tiny batch to practice with.
 

Chris_S

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I don't know how to do this :-(
irish lass has made a topic on how to do the zap test think its under the lye based soap section i would do a here link but no idea how you do that. Hope this helps though. I made the mistake of making too big batches to begin with and once I learnt my lesson I reduced them quite significantly and even now ill only make one small loaf mould for a new recipe :)

Edit just checked and yes its pinned on the lye based forum so its one of the first topics she explains in there how to do the zap test safely
 
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earlene

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What was the result of your zap test? And how old is the soap?

I would suggest that if you want to hold onto this soap to see how it turns out over time, that you keep it separate from your soaps that you are confident are safe (hopefully via zap testing). I would put it in a different location and clearly label it so you or someone else doesn't accidentally bath with it or wash their faces with it prior to a clear zap test. It could take a very long time for all the excess lye to migrate out of that soap, which I believe will produce a huge amount of soda ash developing on the surface over time. If you take a bar out and cut it in halves or quarters and do a zap test of the inside surfaces periodically, that will give you an idea of how long it might take for this soap to become skin safe.

I have some Andalusian Castile I made in January 2017, so just over 2 years old now, and it is skin safe at this point (zap-free). But I didn't maintain a regular schedule for zap testing it, nor document it, so cannot tell you how long it took to become zap-free. I can tell you the exact lye heaviness, though. I made it with a -40% lye concentration, meaning NEGATIVE 40 %, which was purposefully lye heavy as is what defines it as Andalusian (maybe not necessarily always a negative 40 percent, but quite lye heavy, correct?)

Anyway, although it is now skin safe, it's not as kind to my skin as my other Castile soaps. It really dries out my skin even though it is zap-free.

Another thing you can do with lye-heavy soap, is to make it into laundry soap, if it is not too heavily colored, that is.
 
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